package main

import (
    "log"
    "net/http"
    "database/sql"
    "context"
    "strings"

    _ "github.com/mattn/go-sqlite3"

    "stevenlr.com/timer/view"
    "stevenlr.com/timer/model"
)

func insertTimer(tx *sql.Tx, name string) error {
    now := model.MakeTimeNow()
    id := model.MakeUUID()
    _, err := tx.Exec(`
        INSERT INTO Timer VALUES ($1, $2, $3, $4)`, id, name, now, now);
    return err
}

func initializeDatabase(db *sql.DB) error {
    tx, err := db.Begin()
    if err != nil { return err }
    defer tx.Rollback()

    _, err = tx.Exec(`
        CREATE TABLE Timer (
            Id          BLOB    NOT NULL UNIQUE,
            Name        TEXT    NOT NULL,
            StartTime   TEXT    NOT NULL,
            EndTime     TEXT    NOT NULL,
            PRIMARY KEY (id)
        )
    `)
    if err != nil { return err }

    err = insertTimer(tx, "My timer")
    if err != nil { return err }

    err = insertTimer(tx, "My timer2")
    if err != nil { return err }

    return tx.Commit()
}

func queryAllTimers(db *sql.DB) []model.Timer {
    rows, err := db.Query("SELECT Id, Name FROM Timer")
    if err != nil { log.Fatalln(err) }

    timers := []model.Timer{}
    for rows.Next() {
        var t model.Timer
        if err := rows.Scan(&t.Id, &t.Name); err == nil {
            timers = append(timers, t)
        }
    }

    return timers
}

func queryTimer(db *sql.DB, idStr string) *model.Timer {
    var id model.UUID
    if err := id.Scan(idStr); err != nil { return nil }

    row := db.QueryRow("SELECT Id, Name, StartTime, EndTime FROM Timer WHERE Id=$1", id)

    var t model.Timer
    if err := row.Scan(&t.Id, &t.Name, &t.StartTime, &t.EndTime); err == nil {
        return &t
    }

    return nil
}

func deleteTimer(db *sql.DB, idStr string) bool {
    var id model.UUID
    if err := id.Scan(idStr); err != nil { return false }

    res, err := db.Exec("DELETE FROM Timer WHERE Id=$1", id)
    if err != nil { return false }

    affected, err := res.RowsAffected()
    return err == nil && affected > 0
}

type MyServer struct {
    db *sql.DB
}

func (server *MyServer) handleNotFound(w http.ResponseWriter, _ *http.Request) {
    w.WriteHeader(http.StatusNotFound)
    view.Main(view.Error404()).Render(context.Background(), w)
}

func (server *MyServer) handleMain(w http.ResponseWriter, r *http.Request) {
    if r.URL.Path == "/" {
        timers := queryAllTimers(server.db)
        view.Main(view.TimersList(timers)).Render(context.Background(), w)
    } else {
        server.handleNotFound(w, r)
    }
}

func (server *MyServer) handleTimer(w http.ResponseWriter, r *http.Request) {
    timer := queryTimer(server.db, r.PathValue("timerId"))
    if timer != nil {
        view.Main(view.TimerView(*timer)).Render(context.Background(), w)
    } else {
        server.handleNotFound(w, r)
    }
}

func (server *MyServer) handleDeleteTimer(w http.ResponseWriter, r *http.Request) {
    success := deleteTimer(server.db, r.PathValue("timerId"))
    if !success {
        w.WriteHeader(http.StatusNotFound)
    }
}

func (server* MyServer) handlePutTimer(w http.ResponseWriter, r *http.Request) {
    timerName := strings.TrimSpace(r.FormValue("timerName"))

    tx, err := server.db.Begin()
    if err != nil {
        w.WriteHeader(http.StatusInternalServerError)
        view.TimerCreateForm(timerName, "Internal server error").Render(context.Background(), w)
        return
    }
    defer tx.Rollback()

    if timerName == "" {
        w.WriteHeader(http.StatusBadRequest)
        view.TimerCreateForm("", "Timer name cannot be empty").Render(context.Background(), w)
        return
    }

    err = insertTimer(tx, timerName)
    if err != nil {
        w.WriteHeader(http.StatusInternalServerError)
        view.TimerCreateForm(timerName, "Internal server error").Render(context.Background(), w)
        return
    }

    tx.Commit()

    timers := queryAllTimers(server.db)
    view.TimersList(timers).Render(context.Background(), w)
}

func main() {
    log.Println("Starting...")

    db, err := sql.Open("sqlite3", ":memory:")
    if err != nil {
        log.Fatalln(err)
    }
    defer db.Close()

    if err := initializeDatabase(db); err != nil {
        log.Fatalln(err)
    }

    myServer := MyServer{ db: db }

    fs := http.FileServer(http.Dir("static/"))
    http.Handle("GET /static/", http.StripPrefix("/static/", fs))

    http.HandleFunc("GET /timer/{timerId}", myServer.handleTimer)
    http.HandleFunc("DELETE /timer/{timerId}", myServer.handleDeleteTimer)
    http.HandleFunc("PUT /timer", myServer.handlePutTimer)
    http.HandleFunc("GET /", myServer.handleMain)

    log.Println("Started!")
    http.ListenAndServe("0.0.0.0:80", nil)
}