package main

import (
	"bufio"
	"database/sql"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"runtime/debug"
	"strconv"

	c "git.tuxpa.in/a/gosora/common"
	qgen "git.tuxpa.in/a/gosora/query_gen"
	_ "github.com/go-sql-driver/mysql"
)

var patches = make(map[int]func(*bufio.Scanner) error)

func addPatch(index int, handle func(*bufio.Scanner) error) {
    patches[index] = handle
}

func main() {
    scanner := bufio.NewScanner(os.Stdin)

    // Capture panics instead of closing the window at a superhuman speed before the user can read the message on Windows
    defer func() {
        if r := recover(); r != nil {
            fmt.Println(r)
            debug.PrintStack()
            pressAnyKey(scanner)
            log.Fatal("")
            return
        }
    }()

    log.Print("Loading the configuration data")
    err := c.LoadConfig()
    if err != nil {
        log.Fatal(err)
    }

    log.Print("Processing configuration data")
    err = c.ProcessConfig()
    if err != nil {
        log.Fatal(err)
    }

    if c.DbConfig.Adapter != "mysql" && c.DbConfig.Adapter != "" {
        log.Fatal("Only MySQL is supported for upgrades right now, please wait for a newer build of the patcher")
    }

    err = prepMySQL()
    if err != nil {
        log.Fatal(err)
    }

    err = patcher(scanner)
    if err != nil {
        log.Fatal(err)
    }
}

func pressAnyKey(scanner *bufio.Scanner) {
    fmt.Println("Please press enter to exit...")
    for scanner.Scan() {
        _ = scanner.Text()
        return
    }
}

func prepMySQL() error {
    return qgen.Builder.Init("mysql", map[string]string{
        "host":      c.DbConfig.Host,
        "port":      c.DbConfig.Port,
        "name":      c.DbConfig.Dbname,
        "username":  c.DbConfig.Username,
        "password":  c.DbConfig.Password,
        "collation": "utf8mb4_general_ci",
    })
}

type SchemaFile struct {
    DBVersion          string // Current version of the database schema
    DynamicFileVersion string
    MinGoVersion       string // TODO: Minimum version of Go needed to install this version
    MinVersion         string // TODO: Minimum version of Gosora to jump to this version, might be tricky as we don't store this in the schema file, maybe store it in the database
}

func loadSchema() (schemaFile SchemaFile, err error) {
    fmt.Println("Loading the schema file")
    data, err := ioutil.ReadFile("./schema/lastSchema.json")
    if err != nil {
        return schemaFile, err
    }
    err = json.Unmarshal(data, &schemaFile)
    return schemaFile, err
}

func patcher(scanner *bufio.Scanner) error {
    var dbVersion int
    err := qgen.NewAcc().Select("updates").Columns("dbVersion").QueryRow().Scan(&dbVersion)
    if err == sql.ErrNoRows {
        schemaFile, err := loadSchema()
        if err != nil {
            return err
        }
        dbVersion, err = strconv.Atoi(schemaFile.DBVersion)
        if err != nil {
            return err
        }
    } else if err != nil {
        return err
    }

    fmt.Println("Applying the patches")
    var pslice = make([]func(*bufio.Scanner) error, len(patches))
    for i := 0; i < len(patches); i++ {
        pslice[i] = patches[i]
    }

    // Run the queued up patches
    var patched int
    for index, patch := range pslice {
        if dbVersion > index {
            continue
        }
        err := patch(scanner)
        if err != nil {
            fmt.Println("Failed to apply patch " + strconv.Itoa(index+1))
            return err
        }
        fmt.Println("Applied patch " + strconv.Itoa(index+1))
        patched++
    }

    if patched > 0 {
        _, err := qgen.NewAcc().Update("updates").Set("dbVersion = ?").Exec(len(pslice))
        if err != nil {
            return err
        }
    } else {
        fmt.Println("No new patches found.")
    }

    return nil
}