package logcompiler

import (
	"io"
	"sync"
	"time"

	"github.com/D4-project/analyzer-d4-log/inputreader"
	"github.com/gomodule/redigo/redis"
)

type (
	// Compiler provides the interface for a Compiler
	// It should provide:
	//  Set to assign a redis connection to it
	//  Parse to parse a line of log
	//  Flush recomputes statisitcs and recompile output
	Compiler interface {
		Set(*sync.WaitGroup, *redis.Conn, *redis.Conn, io.Reader, int, *sync.WaitGroup, *chan error, time.Duration)
		SetReader(io.Reader)
		Pull(chan error)
		Flush() error
	}

	// CompilerStruct will implements Compiler, and should be embedded in
	// each type implementing compiler
	CompilerStruct struct {
		// Compiler redis Read
		r0 *redis.Conn
		// Compiler redis Write
		r1 *redis.Conn
		// Input Reader
		reader io.Reader
		// Number of line to process before triggering output
		compilationTrigger int
		// Current line processed
		nbLines int
		// Global WaitGroup to handle graceful exiting a compilation routines
		compilegr *sync.WaitGroup
		// Goroutines error channel
		pullreturn *chan error
		// Comutex embedding
		comutex
		// retry Period when applicable
		retryPeriod time.Duration
	}

	comutex struct {
		mu        sync.Mutex
		compiling bool
	}
)

// Set set the redis connections to this compiler
func (s *CompilerStruct) Set(wg *sync.WaitGroup, rconn0 *redis.Conn, rconn1 *redis.Conn, reader io.Reader, ct int, compilegr *sync.WaitGroup, c *chan error, retry time.Duration) {
	s.r0 = rconn0
	s.r1 = rconn1
	s.reader = reader
	s.compilationTrigger = ct
	s.compiling = false
	s.compilegr = compilegr
	s.pullreturn = c
	s.retryPeriod = retry
}

// SetReader Changes compiler's input
func (s *CompilerStruct) SetReader(reader io.Reader) {
	s.reader = reader
}

// tear down is called on error to close redis connections
// and log errors
func (s *CompilerStruct) teardown(err error) {
	*s.pullreturn <- err
	(*s.r0).Close()
	(*s.r1).Close()

	// If the reader is a LPOPReader, we need to teardown the connection
	switch s.reader.(type) {
	case *inputreader.RedisLPOPReader:
		tmp := *s.reader.(*inputreader.RedisLPOPReader)
		tmp.Teardown()
	}
}