package fic

import (
	"database/sql"
	"log"
	"os"
	"time"
	_ "github.com/go-sql-driver/mysql"
)

// db stores the connection to the database
var db *sql.DB

// DSNGenerator returns DSN filed with values from environment
func DSNGenerator() string {
	db_user := "fic"
	db_password := "fic"
	db_host := ""
	db_db := "fic"

	if v, exists := os.LookupEnv("MYSQL_HOST"); exists {
		db_host = v
	}
	if v, exists := os.LookupEnv("MYSQL_PASSWORD"); exists {
		db_password = v
	} else if v, exists := os.LookupEnv("MYSQL_ROOT_PASSWORD"); exists {
		db_user = "root"
		db_password = v
	}
	if v, exists := os.LookupEnv("MYSQL_USER"); exists {
		db_user = v
	}
	if v, exists := os.LookupEnv("MYSQL_DATABASE"); exists {
		db_db = v
	}

	return db_user + ":" + db_password + "@" + db_host + "/" + db_db
}

// DBInit establishes the connection to the database
func DBInit(dsn string) (err error) {
	if db, err = sql.Open("mysql", dsn + "?parseTime=true&foreign_key_checks=1"); err != nil {
		return
	}

	_, err = db.Exec(`SET SESSION sql_mode = 'STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO';`)
	for i := 0; err != nil && i < 15; i += 1 {
		if _, err = db.Exec(`SET SESSION sql_mode = 'STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO';`); err != nil && i <= 5 {
			log.Println("An error occurs when trying to connect to DB, will retry in 2 seconds: ", err)
			time.Sleep(2 * time.Second)
		}
	}

	return
}

// DBCreate creates all necessary tables used by the package
func DBCreate() error {
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS events(
  id_event INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  txt VARCHAR(255) NOT NULL,
  kind ENUM('alert-primary', 'alert-secondary', 'alert-success', 'alert-danger', 'alert-warning', 'alert-info', 'alert-light', 'alert-dark') NOT NULL,
  time TIMESTAMP NOT NULL
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS themes(
  id_theme INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(255) NOT NULL UNIQUE,
  url_id VARCHAR(255) NOT NULL UNIQUE,
  intro TEXT NOT NULL,
  authors TEXT NOT NULL
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS teams(
  id_team INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(255) NOT NULL,
  color INTEGER NOT NULL
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS certificates(
  id_cert BIGINT UNSIGNED NOT NULL PRIMARY KEY AUTO_INCREMENT,
  creation TIMESTAMP NOT NULL,
  password VARCHAR(255) NOT NULL,
  revoked TIMESTAMP NULL
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS team_members(
  id_member INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  id_team INTEGER,
  firstname VARCHAR(255) NOT NULL,
  lastname VARCHAR(255) NOT NULL,
  nickname VARCHAR(255) NOT NULL,
  company VARCHAR(255) NOT NULL,
  FOREIGN KEY(id_team) REFERENCES teams(id_team)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS exercices(
  id_exercice INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  id_theme INTEGER NOT NULL,
  title VARCHAR(255) NOT NULL,
  url_id VARCHAR(255) NOT NULL,
  path VARCHAR(255) NOT NULL,
  statement TEXT NOT NULL,
  overview TEXT NOT NULL,
  depend INTEGER,
  gain INTEGER NOT NULL,
  coefficient_cur FLOAT NOT NULL DEFAULT 1.0,
  video_uri VARCHAR(255) NOT NULL,
  FOREIGN KEY(id_theme) REFERENCES themes(id_theme),
  FOREIGN KEY(depend) REFERENCES exercices(id_exercice)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS exercice_files(
  id_file INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  origin VARCHAR(255) NOT NULL,
  path VARCHAR(255) NOT NULL UNIQUE,
  id_exercice INTEGER NOT NULL,
  name VARCHAR(255) NOT NULL,
  cksum BINARY(64) NOT NULL,
  size INTEGER NOT NULL,
  FOREIGN KEY(id_exercice) REFERENCES exercices(id_exercice)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS exercice_hints(
  id_hint INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  id_exercice INTEGER NOT NULL,
  title VARCHAR(255) NOT NULL,
  content TEXT NOT NULL,
  cost INTEGER NOT NULL,
  FOREIGN KEY(id_exercice) REFERENCES exercices(id_exercice)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS exercice_keys(
  id_key INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  id_exercice INTEGER NOT NULL,
  type VARCHAR(255) NOT NULL,
  cksum BINARY(64) NOT NULL,
  FOREIGN KEY(id_exercice) REFERENCES exercices(id_exercice)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS exercice_mcq(
  id_mcq INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  id_exercice INTEGER NOT NULL,
  title VARCHAR(255) NOT NULL,
  FOREIGN KEY(id_exercice) REFERENCES exercices(id_exercice)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS mcq_entries(
  id_mcq_entry INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  id_mcq INTEGER NOT NULL,
  label VARCHAR(255) NOT NULL,
  response BOOLEAN NOT NULL,
  FOREIGN KEY(id_mcq) REFERENCES exercice_mcq(id_mcq)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS mcq_found(
  id_mcq INTEGER NOT NULL,
  id_team INTEGER NOT NULL,
  time TIMESTAMP NOT NULL,
  CONSTRAINT uq_found UNIQUE (id_mcq,id_team),
  FOREIGN KEY(id_mcq) REFERENCES exercice_mcq(id_mcq),
  FOREIGN KEY(id_team) REFERENCES teams(id_team)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS key_found(
  id_key INTEGER NOT NULL,
  id_team INTEGER NOT NULL,
  time TIMESTAMP NOT NULL,
  CONSTRAINT uc_found UNIQUE (id_key,id_team),
  FOREIGN KEY(id_key) REFERENCES exercice_keys(id_key),
  FOREIGN KEY(id_team) REFERENCES teams(id_team)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS exercice_solved(
  id_exercice INTEGER NOT NULL,
  id_team INTEGER NOT NULL,
  time TIMESTAMP NOT NULL,
  coefficient FLOAT NOT NULL DEFAULT 1.0,
  CONSTRAINT uc_solved UNIQUE (id_exercice,id_team),
  FOREIGN KEY(id_exercice) REFERENCES exercices(id_exercice),
  FOREIGN KEY(id_team) REFERENCES teams(id_team)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS exercice_tries(
  id_exercice INTEGER NOT NULL,
  id_team INTEGER NOT NULL,
  time TIMESTAMP NOT NULL,
  nbdiff INTEGER NOT NULL DEFAULT 0,
  FOREIGN KEY(id_exercice) REFERENCES exercices(id_exercice),
  FOREIGN KEY(id_team) REFERENCES teams(id_team)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS team_hints(
  id_team INTEGER,
  id_hint INTEGER,
  time TIMESTAMP NOT NULL,
  CONSTRAINT uc_displayed UNIQUE (id_team,id_hint),
  FOREIGN KEY(id_hint) REFERENCES exercice_hints(id_hint),
  FOREIGN KEY(id_team) REFERENCES teams(id_team)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS claim_assignees(
  id_assignee INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(255) NOT NULL UNIQUE
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS claims(
  id_claim INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  subject VARCHAR(255) NOT NULL,
  id_team INTEGER,
  id_assignee INTEGER,
  creation TIMESTAMP NOT NULL,
  state ENUM('new', 'need-info', 'confirmed', 'in-progress', 'need-review', 'closed', 'invalid') NOT NULL,
  priority ENUM('low', 'medium', 'high', 'critical') NOT NULL,
  FOREIGN KEY(id_assignee) REFERENCES claim_assignees(id_assignee),
  FOREIGN KEY(id_team) REFERENCES teams(id_team)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	if _, err := db.Exec(`
CREATE TABLE IF NOT EXISTS claim_descriptions(
  id_description INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
  id_claim INTEGER NOT NULL,
  id_assignee INTEGER NOT NULL,
  date TIMESTAMP NOT NULL,
  content TEXT NOT NULL,
  FOREIGN KEY(id_assignee) REFERENCES claim_assignees(id_assignee),
  FOREIGN KEY(id_claim) REFERENCES claims(id_claim)
) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
`); err != nil {
		return err
	}
	return nil
}

// DBClose closes the connection to the database
func DBClose() error {
	return db.Close()
}

func DBPrepare(query string) (*sql.Stmt, error) {
	return db.Prepare(query)
}

func DBQuery(query string, args ...interface{}) (*sql.Rows, error) {
	return db.Query(query, args...)
}

func DBExec(query string, args ...interface{}) (sql.Result, error) {
	return db.Exec(query, args...)
}

func DBQueryRow(query string, args ...interface{}) *sql.Row {
	return db.QueryRow(query, args...)
}