package main

import "core:fmt"
import "core:net"
import "core:os"
import "core:strconv"
import "core:strings"
import "core:sync"
import "core:thread"
import "core:time"
import json "core:encoding/json"

Protocol_Message_Kind :: enum {
    Invalid,
    Response,
    Event,
}

Protocol_Message :: struct {
    kind:  Protocol_Message_Kind,
    id:    int,
    ok:    bool,
    event: string,
}

Daemon_Response :: struct {
    id:   int,
    line: [dynamic]u8,
}

Daemon_Event :: struct {
    line: [dynamic]u8,
}

Daemon_Process :: struct {
    process: os.Process,
    stdout:  ^os.File,
    running: bool,
}

Daemon_Client :: struct {
    socket:       net.TCP_Socket,
    connected:    bool,
    next_id:      int,
    reader:       ^thread.Thread,
    event_mutex:  sync.Mutex,
    response_mutex: sync.Mutex,
    diagnostic_events: [dynamic]Daemon_Event,
    gradle_events: [dynamic]Daemon_Event,
    pending_response_ids: [dynamic]int,
    responses: [dynamic]Daemon_Response,
}

daemon_connect :: proc(port: int) -> Daemon_Client {
    client := Daemon_Client{next_id = 1}
    if port <= 0 do return client

    socket, err := net.dial_tcp("127.0.0.1", port)
    if err != nil {
        fmt.println("daemon connect failed:", err)
        return client
    }

    client.socket = socket
    client.connected = true
    return client
}

daemon_start_process :: proc(workspace: string) -> (Daemon_Process, int, bool) {
    child, ok := daemon_start_process_begin(workspace)
    if !ok {
        return child, 0, false
    }

    port, port_ok := daemon_read_port(&child)
    if !port_ok {
        daemon_stop_process(&child)
        return child, 0, false
    }
    return child, port, true
}

daemon_start_process_begin :: proc(workspace: string) -> (Daemon_Process, bool) {
    child := Daemon_Process{}

    stdout_r, stdout_w, pipe_err := os.pipe()
    if pipe_err != nil {
        fmt.println("daemon pipe failed:", pipe_err)
        return child, false
    }

    command := []string{"gradle", "-p", workspace, "run", "--quiet"}
    process, start_err := os.process_start(os.Process_Desc{
        command = command,
        stdout = stdout_w,
    })
    _ = os.close(stdout_w)

    if start_err != nil {
        fmt.println("daemon start failed:", start_err)
        _ = os.close(stdout_r)
        return child, false
    }

    child = Daemon_Process{process = process, stdout = stdout_r, running = true}
    return child, true
}

daemon_stop_process :: proc(child: ^Daemon_Process) {
    if child.stdout != nil {
        _ = os.close(child.stdout)
        child.stdout = nil
    }
    if child.running {
        _ = os.process_terminate(child.process)
        state, wait_err := os.process_wait(child.process, 2 * time.Second)
        if wait_err != nil || !state.exited {
            _ = os.process_kill(child.process)
            _, _ = os.process_wait(child.process)
        }
        child.running = false
    }
}

daemon_read_port :: proc(child: ^Daemon_Process) -> (int, bool) {
    line: [dynamic]u8
    defer delete(line)

    start := time.now()
    buf: [1024]u8
    for time.diff(start, time.now()) < 30 * time.Second {
        state, wait_err := os.process_wait(child.process, 0)
        if wait_err == nil && state.exited {
            fmt.println("daemon exited before announcing port")
            return 0, false
        }

        has_data, data_err := os.pipe_has_data(child.stdout)
        if data_err != nil {
            fmt.println("daemon stdout failed:", data_err)
            return 0, false
        }
        if !has_data {
            time.sleep(100 * time.Millisecond)
            continue
        }

        n, read_err := os.read(child.stdout, buf[:])
        if read_err != nil {
            fmt.println("daemon stdout read failed:", read_err)
            return 0, false
        }

        for b in buf[:n] {
            if b == '\n' {
                port, ok := daemon_parse_port_line(string(line[:]))
                if ok do return port, true
                clear(&line)
            } else {
                append(&line, b)
            }
        }
    }

    fmt.println("daemon start timed out")
    return 0, false
}

daemon_poll_port :: proc(child: ^Daemon_Process, line: ^[dynamic]u8) -> (int, bool, bool) {
    if child == nil || !child.running || child.stdout == nil do return 0, false, true

    state, wait_err := os.process_wait(child.process, 0)
    if wait_err == nil && state.exited {
        fmt.println("daemon exited before announcing port")
        return 0, false, true
    }

    has_data, data_err := os.pipe_has_data(child.stdout)
    if data_err != nil {
        fmt.println("daemon stdout failed:", data_err)
        return 0, false, true
    }
    if !has_data do return 0, false, false

    buf: [1024]u8
    n, read_err := os.read(child.stdout, buf[:])
    if read_err != nil {
        fmt.println("daemon stdout read failed:", read_err)
        return 0, false, true
    }

    for b in buf[:n] {
        if b == '\n' {
            port, ok := daemon_parse_port_line(string(line[:]))
            clear(line)
            if ok do return port, true, false
        } else {
            append(line, b)
        }
    }

    return 0, false, false
}

daemon_parse_port_line :: proc(line: string) -> (int, bool) {
    if !strings.has_prefix(line, "PORT ") do return 0, false
    port, ok := strconv.parse_int(line[len("PORT "):])
    if !ok do return 0, false
    return int(port), true
}

daemon_start_reader :: proc(client: ^Daemon_Client) {
    if client.connected && client.reader == nil {
        client.reader = thread.create_and_start_with_data(rawptr(client), daemon_reader_thread)
    }
}

daemon_close :: proc(client: ^Daemon_Client) {
    if client.connected {
        net.close(client.socket)
        client.connected = false
    }
    if client.reader != nil && thread.is_done(client.reader) {
        thread.destroy(client.reader)
        client.reader = nil
    }
    for &event in client.diagnostic_events {
        delete(event.line)
    }
    delete(client.diagnostic_events)
    client.diagnostic_events = nil
    for &event in client.gradle_events {
        delete(event.line)
    }
    delete(client.gradle_events)
    client.gradle_events = nil
    delete(client.pending_response_ids)
    client.pending_response_ids = nil
    for &response in client.responses {
        delete(response.line)
    }
    delete(client.responses)
    client.responses = nil
}

daemon_send :: proc(client: ^Daemon_Client, message: string) {
    if !client.connected do return
    bytes := transmute([]byte)message
    _, err := net.send_tcp(client.socket, bytes)
    if err != nil {
        fmt.println("daemon send failed:", err)
        daemon_close(client)
    }
}

daemon_track_response :: proc(client: ^Daemon_Client, id: int) {
    if id == 0 do return
    if sync.mutex_guard(&client.response_mutex) {
        append(&client.pending_response_ids, id)
    }
}

daemon_send_workspace_open :: proc(client: ^Daemon_Client, workspace: string) {
    if !client.connected do return
    id := client.next_id
    client.next_id += 1
    request := fmt.tprintf("{{\"id\":%d,\"method\":\"workspace/open\",\"params\":{{\"root\":%q}}}}\n", id, workspace)
    daemon_send(client, request)
}

daemon_send_text_open :: proc(client: ^Daemon_Client, path: string, version: int, text: string) {
    if !client.connected do return
    id := client.next_id
    client.next_id += 1
    request := fmt.tprintf("{{\"id\":%d,\"method\":\"text/open\",\"params\":{{\"path\":%q,\"version\":%d,\"text\":%q}}}}\n", id, path, version, text)
    daemon_send(client, request)
}

daemon_send_text_change :: proc(client: ^Daemon_Client, path: string, version: int, text: string) {
    if !client.connected do return
    id := client.next_id
    client.next_id += 1
    request := fmt.tprintf("{{\"id\":%d,\"method\":\"text/change\",\"params\":{{\"path\":%q,\"version\":%d,\"text\":%q}}}}\n", id, path, version, text)
    daemon_send(client, request)
}

daemon_send_completion :: proc(client: ^Daemon_Client, path: string, line, column: int) -> int {
    if !client.connected do return 0
    id := client.next_id
    client.next_id += 1
    request := fmt.tprintf("{{\"id\":%d,\"method\":\"kotlin/completion\",\"params\":{{\"path\":%q,\"line\":%d,\"column\":%d}}}}\n", id, path, line + 1, column + 1)
    daemon_track_response(client, id)
    daemon_send(client, request)
    return id
}

daemon_send_hover :: proc(client: ^Daemon_Client, path: string, line, column: int) -> int {
    if !client.connected do return 0
    id := client.next_id
    client.next_id += 1
    request := fmt.tprintf("{{\"id\":%d,\"method\":\"kotlin/hover\",\"params\":{{\"path\":%q,\"line\":%d,\"column\":%d}}}}\n", id, path, line + 1, column + 1)
    daemon_track_response(client, id)
    daemon_send(client, request)
    return id
}

daemon_send_definition :: proc(client: ^Daemon_Client, path: string, line, column: int) -> int {
    if !client.connected do return 0
    id := client.next_id
    client.next_id += 1
    request := fmt.tprintf("{{\"id\":%d,\"method\":\"kotlin/definition\",\"params\":{{\"path\":%q,\"line\":%d,\"column\":%d}}}}\n", id, path, line + 1, column + 1)
    daemon_track_response(client, id)
    daemon_send(client, request)
    return id
}

daemon_send_references :: proc(client: ^Daemon_Client, path: string, line, column: int) -> int {
    if !client.connected do return 0
    id := client.next_id
    client.next_id += 1
    request := fmt.tprintf("{{\"id\":%d,\"method\":\"kotlin/references\",\"params\":{{\"path\":%q,\"line\":%d,\"column\":%d}}}}\n", id, path, line + 1, column + 1)
    daemon_track_response(client, id)
    daemon_send(client, request)
    return id
}

daemon_send_rename :: proc(client: ^Daemon_Client, path: string, line, column: int, new_name: string) -> int {
    if !client.connected do return 0
    id := client.next_id
    client.next_id += 1
    request := fmt.tprintf("{{\"id\":%d,\"method\":\"kotlin/rename\",\"params\":{{\"path\":%q,\"line\":%d,\"column\":%d,\"newName\":%q}}}}\n", id, path, line + 1, column + 1, new_name)
    daemon_track_response(client, id)
    daemon_send(client, request)
    return id
}

daemon_send_gradle_tasks :: proc(client: ^Daemon_Client) -> int {
    if !client.connected do return 0
    id := client.next_id
    client.next_id += 1
    request := fmt.tprintf("{{\"id\":%d,\"method\":\"gradle/tasks\",\"params\":{{}}}}\n", id)
    daemon_track_response(client, id)
    daemon_send(client, request)
    return id
}

daemon_send_gradle_run :: proc(client: ^Daemon_Client, task: string) -> int {
    if !client.connected do return 0
    id := client.next_id
    client.next_id += 1
    request := fmt.tprintf("{{\"id\":%d,\"method\":\"gradle/run\",\"params\":{{\"task\":%q}}}}\n", id, task)
    daemon_track_response(client, id)
    daemon_send(client, request)
    return id
}

daemon_sync_active_buffer :: proc(client: ^Daemon_Client, editor: ^Editor, open: bool) {
    active := editor_active_buffer(editor)
    if active == nil do return

    text := editor_active_text(editor)
    defer delete(text)

    if open {
        daemon_send_text_open(client, active.path, active.buffer.version, string(text[:]))
    } else {
        daemon_send_text_change(client, active.path, active.buffer.version, string(text[:]))
    }
}

daemon_reader_thread :: proc(data: rawptr) {
    client := (^Daemon_Client)(data)
    buf: [4096]u8
    line: [dynamic]u8
    defer delete(line)

    for client.connected {
        n, err := net.recv_tcp(client.socket, buf[:])
        if err != nil || n == 0 {
            client.connected = false
            break
        }

        for b in buf[:n] {
            if b == '\n' {
                daemon_store_line(client, string(line[:]))
                clear(&line)
            } else {
                append(&line, b)
            }
        }
    }
}

daemon_store_line :: proc(client: ^Daemon_Client, line: string) {
    message, value, ok := parse_protocol_message(line)
    if !ok do return
    defer json.destroy_value(value)
    if message.kind == .Response {
        if sync.mutex_guard(&client.response_mutex) {
            tracked := false
            for pending_id, index in client.pending_response_ids {
                if pending_id == message.id {
                    ordered_remove(&client.pending_response_ids, index)
                    tracked = true
                    break
                }
            }
            if !tracked do return

            response := Daemon_Response{id = message.id}
            for b in transmute([]u8)line {
                append(&response.line, b)
            }
            append(&client.responses, response)
        }
        return
    }
    if message.kind != .Event do return

    if message.event == "gradle/run" {
        if sync.mutex_guard(&client.event_mutex) {
            event := Daemon_Event{}
            for b in transmute([]u8)line {
                append(&event.line, b)
            }
            append(&client.gradle_events, event)
        }
        return
    }

    if message.event != "diagnostics/publish" do return

    if sync.mutex_guard(&client.event_mutex) {
        event := Daemon_Event{}
        for b in transmute([]u8)line {
            append(&event.line, b)
        }
        append(&client.diagnostic_events, event)
    }
}

daemon_take_response :: proc(client: ^Daemon_Client, expected_id: int) -> [dynamic]u8 {
    out: [dynamic]u8
    if expected_id == 0 do return out

    if sync.mutex_guard(&client.response_mutex) {
        for &response, index in client.responses {
            if response.id != expected_id do continue
            for b in response.line {
                append(&out, b)
            }
            delete(response.line)
            ordered_remove(&client.responses, index)
            break
        }
    }
    return out
}

daemon_take_diagnostic_event :: proc(client: ^Daemon_Client) -> [dynamic]u8 {
    out: [dynamic]u8
    if !client.connected && len(client.diagnostic_events) == 0 do return out

    if sync.mutex_guard(&client.event_mutex) {
        if len(client.diagnostic_events) == 0 do return out
        event := client.diagnostic_events[0]
        for b in event.line {
            append(&out, b)
        }
        delete(event.line)
        ordered_remove(&client.diagnostic_events, 0)
    }
    return out
}

daemon_take_gradle_event :: proc(client: ^Daemon_Client) -> [dynamic]u8 {
    out: [dynamic]u8
    if !client.connected && len(client.gradle_events) == 0 do return out

    if sync.mutex_guard(&client.event_mutex) {
        if len(client.gradle_events) == 0 do return out
        event := client.gradle_events[0]
        for b in event.line {
            append(&out, b)
        }
        delete(event.line)
        ordered_remove(&client.gradle_events, 0)
    }
    return out
}

daemon_apply_latest_diagnostics :: proc(client: ^Daemon_Client, editor: ^Editor) {
    for {
        event := daemon_take_diagnostic_event(client)
        if len(event) == 0 {
            delete(event)
            return
        }

        path, diagnostics := parse_diagnostics_event(string(event[:]))
        if len(path) == 0 || !editor_set_diagnostics_for_path(editor, path, diagnostics[:]) {
            diagnostics_destroy(diagnostics[:])
        }
        delete(path)
        delete(diagnostics)
        delete(event)
    }
}

diagnostics_destroy :: proc(diagnostics: []Diagnostic) {
    for diagnostic in diagnostics {
        delete(diagnostic.severity)
        delete(diagnostic.message)
    }
}

parse_diagnostics_event :: proc(event: string) -> (string, [dynamic]Diagnostic) {
    diagnostics: [dynamic]Diagnostic

    message, value, parsed := parse_protocol_message(event)
    if !parsed do return "", diagnostics
    defer json.destroy_value(value)
    if message.kind != .Event || message.event != "diagnostics/publish" do return "", diagnostics

    params, has_params := json_object_get(value, "params")
    if !has_params do return "", diagnostics
    path, _ := json_get_string(params, "path")
    diagnostics_value, has_diagnostics := json_object_get(params, "diagnostics")
    if !has_diagnostics do return strings.clone(path), diagnostics

    #partial switch items in diagnostics_value {
    case json.Array:
        for item in items {
            severity, _ := json_get_string(item, "severity")
            diagnostic_message, _ := json_get_string(item, "message")
            line, _ := json_get_int(item, "line")
            column, _ := json_get_int(item, "column")

            append(&diagnostics, Diagnostic{
                line = max_int(line - 1, 0),
                column = max_int(column - 1, 0),
                severity = strings.clone(severity),
                message = strings.clone(diagnostic_message),
            })
        }
    }

    return strings.clone(path), diagnostics
}

parse_protocol_message :: proc(line: string) -> (Protocol_Message, json.Value, bool) {
    value, err := json.parse_string(line, .JSON, true)
    if err != nil {
        return Protocol_Message{}, value, false
    }

    message := Protocol_Message{}
    if event, ok := json_get_string(value, "event"); ok {
        message.kind = .Event
        message.event = event
        return message, value, true
    }

    if id, ok := json_get_int(value, "id"); ok {
        message.kind = .Response
        message.id = id
        message.ok, _ = json_get_bool(value, "ok")
        return message, value, true
    }

    return message, value, false
}

json_object_get :: proc(value: json.Value, key: string) -> (json.Value, bool) {
    #partial switch object in value {
    case json.Object:
        if item, ok := object[key]; ok {
            return item, true
        }
    }
    return json.Value{}, false
}

json_get_string :: proc(value: json.Value, key: string) -> (string, bool) {
    item, ok := json_object_get(value, key)
    if !ok do return "", false
    #partial switch s in item {
    case json.String:
        return string(s), true
    }
    return "", false
}

json_get_int :: proc(value: json.Value, key: string) -> (int, bool) {
    item, ok := json_object_get(value, key)
    if !ok do return 0, false
    #partial switch n in item {
    case json.Integer:
        return int(n), true
    case json.Float:
        return int(n), true
    }
    return 0, false
}

json_get_bool :: proc(value: json.Value, key: string) -> (bool, bool) {
    item, ok := json_object_get(value, key)
    if !ok do return false, false
    #partial switch b in item {
    case json.Boolean:
        return bool(b), true
    }
    return false, false
}