package fic

import (
	"errors"
	"fmt"
	"time"
)

// MCQ represents a flag's challenge, in the form of checkbox.
type MCQ struct {
	Id int `json:"id"`
	// IdExercice is the identifier of the underlying challenge
	IdExercice int64 `json:"idExercice"`
	// Order is used to sort the flag between them
	Order int8 `json:"order"`
	// Title is the label of the question
	Title string `json:"title"`
	// Entries stores the set of proposed answers
	Entries []*MCQ_entry `json:"entries"`
}

// MCQ_entry represents a proposed response for a given MCQ.
type MCQ_entry struct {
	Id int `json:"id"`
	// Label is the text displayed to players as proposed answer
	Label string `json:"label"`
	// Response stores if expected checked state.
	Response bool `json:"response"`
}

// GetMCQ returns a list of flags comming with the challenge.
func GetMCQ(id int) (m *MCQ, err error) {
	m = &MCQ{}
	err = DBQueryRow("SELECT id_mcq, id_exercice, ordre, title FROM exercice_mcq WHERE id_mcq = ?", id).Scan(&m.Id, &m.IdExercice, &m.Order, &m.Title)
	m.fillEntries()
	return
}

func (m *MCQ) fillEntries() ([]*MCQ_entry, error) {
	if entries_rows, err := DBQuery("SELECT id_mcq_entry, label, response FROM mcq_entries WHERE id_mcq = ?", m.Id); err != nil {
		return nil, err
	} else {
		defer entries_rows.Close()

		for entries_rows.Next() {
			e := &MCQ_entry{}

			if err := entries_rows.Scan(&e.Id, &e.Label, &e.Response); err != nil {
				return nil, err
			}

			m.Entries = append(m.Entries, e)
		}
	}

	return m.Entries, nil
}

// GetMCQ returns the MCQs coming with the challenge.
func (e *Exercice) GetMCQ() ([]*MCQ, error) {
	if rows, err := DBQuery("SELECT id_mcq, id_exercice, ordre, title FROM exercice_mcq WHERE id_exercice = ?", e.Id); err != nil {
		return nil, err
	} else {
		defer rows.Close()

		var mcqs = []*MCQ{}
		for rows.Next() {
			m := &MCQ{}
			m.IdExercice = e.Id

			if err := rows.Scan(&m.Id, &m.IdExercice, &m.Order, &m.Title); err != nil {
				return nil, err
			}

			m.fillEntries()

			mcqs = append(mcqs, m)
		}
		if err := rows.Err(); err != nil {
			return nil, err
		}

		return mcqs, nil
	}
}

// GetMCQById returns a MCQs.
func (e *Exercice) GetMCQById(id int) (m *MCQ, err error) {
	m = &MCQ{}
	err = DBQueryRow("SELECT id_mcq, id_exercice, ordre, title FROM exercice_mcq WHERE id_mcq = ? AND id_exercice = ?", id, e.Id).Scan(&m.Id, &m.IdExercice, &m.Order, &m.Title)
	m.fillEntries()
	return
}

// GetMCQbyChoice returns the MCQ corresponding to a choice ID.
func GetMCQbyChoice(cid int) (m *MCQ, c *MCQ_entry, err error) {
	m = &MCQ{}
	if errr := DBQueryRow("SELECT id_mcq, id_exercice, ordre, title FROM exercice_mcq WHERE id_mcq = (SELECT id_mcq FROM mcq_entries WHERE id_mcq_entry = ?)", cid).Scan(&m.Id, &m.IdExercice, &m.Order, &m.Title); errr != nil {
		return nil, nil, errr
	}

	if entries_rows, errr := DBQuery("SELECT id_mcq_entry, label, response FROM mcq_entries WHERE id_mcq = ?", m.Id); errr != nil {
		return nil, nil, errr
	} else {
		defer entries_rows.Close()

		for entries_rows.Next() {
			e := &MCQ_entry{}

			if err = entries_rows.Scan(&e.Id, &e.Label, &e.Response); err != nil {
				return
			}

			if e.Id == cid {
				c = e
			}

			m.Entries = append(m.Entries, e)
		}
	}

	return
}

// GetId returns the MCQ identifier.
func (m *MCQ) GetId() int {
	return m.Id
}

// RecoverId returns the MCQ identifier as register in DB.
func (m *MCQ) RecoverId() (Flag, error) {
	if err := DBQueryRow("SELECT id_mcq FROM exercice_mcq WHERE title LIKE ? AND id_exercice = ?", m.Title, m.IdExercice).Scan(&m.Id); err != nil {
		return nil, err
	} else {
		return m, err
	}
}

// Create registers a MCQ into the database and recursively add its entries.
func (m *MCQ) Create(e *Exercice) (Flag, error) {
	if res, err := DBExec("INSERT INTO exercice_mcq (id_exercice, ordre, title) VALUES (?, ?, ?)", e.Id, m.Order, m.Title); err != nil {
		return m, err
	} else if qid, err := res.LastInsertId(); err != nil {
		return m, err
	} else {
		m.Id = int(qid)
		m.IdExercice = e.Id

		// Add entries
		for k, entry := range m.Entries {
			if entry, err = m.AddEntry(entry); err != nil {
				return m, err
			} else {
				m.Entries[k] = entry
			}
		}

		return m, nil
	}
}

// Update applies modifications back to the database.
func (m *MCQ) Update() (int64, error) {
	if res, err := DBExec("UPDATE exercice_mcq SET id_exercice = ?, ordre = ?, title = ? WHERE id_mcq = ?", m.IdExercice, m.Order, m.Title, m.Id); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}

// Delete the MCQ from the database.
func (m *MCQ) Delete() (int64, error) {
	if _, err := DBExec("DELETE FROM exercice_files_omcq_deps WHERE id_mcq = ?", m.Id); err != nil {
		return 0, err
	} else if _, err := DBExec("DELETE FROM exercice_mcq_okey_deps WHERE id_mcq = ?", m.Id); err != nil {
		return 0, err
	} else if _, err := DBExec("DELETE FROM exercice_mcq_omcq_deps WHERE id_mcq = ?", m.Id); err != nil {
		return 0, err
	} else if _, err := DBExec("DELETE FROM exercice_mcq_omcq_deps WHERE id_mcq_dep = ?", m.Id); err != nil {
		return 0, err
	} else if _, err := DBExec("DELETE FROM exercice_flags_omcq_deps WHERE id_mcq_dep = ?", m.Id); err != nil {
		return 0, err
	} else if _, err := DBExec("DELETE FROM exercice_hints_omcq_deps WHERE id_mcq_dep = ?", m.Id); err != nil {
		return 0, err
	} else if res, err := DBExec("DELETE FROM exercice_mcq WHERE id_mcq = ?", m.Id); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}

// AddEntry creates and fills a new struct MCQ_entry and registers it into the database.
func (m *MCQ) AddEntry(e *MCQ_entry) (*MCQ_entry, error) {
	if res, err := DBExec("INSERT INTO mcq_entries (id_mcq, label, response) VALUES (?, ?, ?)", m.Id, e.Label, e.Response); err != nil {
		return e, err
	} else if nid, err := res.LastInsertId(); err != nil {
		return e, err
	} else {
		e.Id = int(nid)
		return e, nil
	}
}

// Update applies modifications back to the database.
func (n *MCQ_entry) Update() (int64, error) {
	if res, err := DBExec("UPDATE mcq_entries SET label = ?, response = ? WHERE id_mcq = ?", n.Label, n.Response, n.Id); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}

// Delete the MCQ entry from the database.
func (n *MCQ_entry) Delete() (int64, error) {
	if res, err := DBExec("DELETE FROM mcq_entries WHERE id_mcq_entry = ?", n.Id); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}

// WipeMCQs deletes MCQs coming with the challenge.
func (e *Exercice) WipeMCQs() (int64, error) {
	if _, err := DBExec("DELETE FROM exercice_files_omcq_deps WHERE id_mcq IN (SELECT id_mcq FROM exercice_mcq WHERE id_exercice = ?)", e.Id); err != nil {
		return 0, err
	} else if _, err := DBExec("DELETE FROM mcq_entries WHERE id_mcq IN (SELECT id_mcq FROM exercice_mcq WHERE id_exercice = ?);", e.Id); err != nil {
		return 0, err
	} else if _, err := DBExec("DELETE FROM exercice_flags_omcq_deps WHERE id_mcq_dep IN (SELECT id_mcq FROM exercice_mcq WHERE id_exercice = ?);", e.Id); err != nil {
		return 0, err
	} else if _, err := DBExec("DELETE FROM exercice_mcq_okey_deps WHERE id_mcq IN (SELECT id_mcq FROM exercice_mcq WHERE id_exercice = ?);", e.Id); err != nil {
		return 0, err
	} else if _, err := DBExec("DELETE FROM exercice_mcq_omcq_deps WHERE id_mcq IN (SELECT id_mcq FROM exercice_mcq WHERE id_exercice = ?);", e.Id); err != nil {
		return 0, err
	} else if _, err := DBExec("DELETE FROM exercice_mcq_omcq_deps WHERE id_mcq_dep IN (SELECT id_mcq FROM exercice_mcq WHERE id_exercice = ?);", e.Id); err != nil {
		return 0, err
	} else if res, err := DBExec("DELETE FROM exercice_mcq WHERE id_exercice = ?;", e.Id); err != nil {
		return 0, err
	} else if nb, err := res.RowsAffected(); err != nil {
		return 0, err
	} else {
		return nb, err
	}
}

func (m *MCQ) GetOrder() int8 {
	return m.Order
}

// AddDepend insert a new dependency to a given flag.
func (m *MCQ) AddDepend(j Flag) (err error) {
	if d, ok := j.(*FlagKey); ok {
		_, err = DBExec("INSERT INTO exercice_mcq_okey_deps (id_mcq, id_flag_dep) VALUES (?, ?)", m.Id, d.Id)
	} else if d, ok := j.(*MCQ); ok {
		_, err = DBExec("INSERT INTO exercice_mcq_omcq_deps (id_mcq, id_mcq_dep) VALUES (?, ?)", m.Id, d.Id)
	} else {
		err = errors.New("dependancy type not implemented for this flag")
	}
	return
}

// GetDepends retrieve the flag's dependency list.
func (m *MCQ) GetDepends() ([]Flag, error) {
	deps := []Flag{}

	if rows, err := DBQuery("SELECT id_flag_dep FROM exercice_mcq_okey_deps WHERE id_mcq = ?", m.Id); err != nil {
		return nil, err
	} else {
		defer rows.Close()

		for rows.Next() {
			var d int
			if err := rows.Scan(&d); err != nil {
				return nil, err
			}
			deps = append(deps, &FlagKey{Id: d, IdExercice: m.IdExercice})
		}
		if err := rows.Err(); err != nil {
			return nil, err
		}

	}

	if rows, err := DBQuery("SELECT id_mcq_dep FROM exercice_mcq_omcq_deps WHERE id_mcq = ?", m.Id); err != nil {
		return nil, err
	} else {
		defer rows.Close()

		for rows.Next() {
			var d int
			if err := rows.Scan(&d); err != nil {
				return nil, err
			}
			deps = append(deps, &MCQ{Id: d, IdExercice: m.IdExercice})
		}
		if err := rows.Err(); err != nil {
			return nil, err
		}

	}

	return deps, nil
}

// GetJustifiedFlag searchs for a flag in the scope of the given exercice.
func (c *MCQ_entry) GetJustifiedFlag(e *Exercice) (*FlagKey, error) {
	return e.GetFlagKeyByLabel(fmt.Sprintf("\\%%%d\\%%%%", c.Id))
}

// IsOptionnal to know if the flag can be omitted when validating the step.
func (m *MCQ) IsOptionnal() bool {
	return false
}

// Check if the given vals are the expected ones to validate this flag.
func (m *MCQ) Check(v interface{}) int {
	var vals map[int]bool
	if va, ok := v.(map[int]bool); !ok {
		return -1
	} else {
		vals = va
	}

	diff := 0

	for _, n := range m.Entries {
		if v, ok := vals[n.Id]; (ok || !n.Response) && v == n.Response {
			continue
		}
		diff += 1
	}

	return diff
}

// FoundBy registers in the database that the given Team solved the MCQ.
func (m *MCQ) FoundBy(t *Team) (err error) {
	_, err = DBExec("INSERT INTO mcq_found (id_mcq, id_team, time) VALUES (?, ?, ?)", m.Id, t.Id, time.Now())
	return
}